40 lines
1.7 KiB
OCaml
40 lines
1.7 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Xavier Leroy and Damien Doligez, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the GNU Library General Public License, with *)
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(* the special exception on linking described in file ../../LICENSE. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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type t = { mutable locked: bool; mutable waiting: Thread.t list }
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let create () = { locked = false; waiting = [] }
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let rec lock m =
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if m.locked then begin (* test and set atomic *)
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Thread.critical_section := true;
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m.waiting <- Thread.self() :: m.waiting;
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Thread.sleep();
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lock m
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end else begin
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m.locked <- true (* test and set atomic *)
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end
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let try_lock m = (* test and set atomic *)
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if m.locked then false else begin m.locked <- true; true end
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let unlock m =
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(* Don't play with Thread.critical_section here because of Condition.wait *)
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let w = m.waiting in (* atomic *)
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m.waiting <- []; (* atomic *)
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m.locked <- false; (* atomic *)
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List.iter Thread.wakeup w
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